The significance of cooling rate on water dynamics in porcine muscle from heterozygote carriers and non-carriers of the halothane gene-a low-field NMR relaxation study.

The post mortem changes in the chemical/physical state distribution of water were followed in pig muscle (M. longissimus dorsi) from heterozygote (n=12) and non-carriers (n=12) of the halothane gene exposed to two different cooling profiles using continuous low-field NMR relaxation measurements. T(2) relaxation data were analyzed using distributed exponential fitting analysis. Independent of genotype post mortem changes were observed in the two water populations characterizing water within the myofibrillar space (T(21)) and the extra-myofibrillar space (T(22)), respectively, as a function of chilling regime. The effect was most pronounced in samples from heterozygote carriers of the halothane gene. The obtained results strongly suggest that improved water-holding capacity of muscles upon fast chilling can be ascribed to a reduced accumulation of extra-myofibrillar water in the meat post mortem, and it is hypothesized that differences in the accumulation of extra-myofibrillar water post mortem can be ascribed largely to the time at which disruption of cell membrane integrity takes place.